Rolling bearing

Abstract

Provided is a rolling bearing with stable sealing properties. The rolling bearing includes an inner ring (2), an outer ring (3), a plurality of rolling bodies interposed between the inner ring (2) and the outer ring (3), and a sealing member (6) that seals a bearing space between the inner ring (2) and the outer ring (3). An outer peripheral side portion (8) of the sealing member (6) is fixed to a seal groove (9) of the outer ring (3), and an inner peripheral side portion (13) of the sealing member (6) is provided with a lip (15) that contacts an outer surface (7c) of the seal groove (7) of the inner ring (2). The sealing member (6) is provided with a seal collapse prevention means (St) for preventing the inner peripheral side portion (13) from collapsing axially inward. The seal collapse prevention means (St) has an inner surface (8a) of the outer peripheral side portion (8) of the sealing member (6) that comes into contact with the seal groove (9) of the outer ring (3) and has an inclined surface (8aa) that is inclined toward the inner diameter side while extending axially inward.

Description

Rolling bearings Related Applications

[0001] This application claims priority to Japanese Patent Application No. 2024-147949 filed on August 29, 2024, and Japanese Patent Application No. 2024-147950 filed on August 29, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a rolling bearing, and to a technique for stabilizing sealing performance.

[0003] 12, there is a model of rolling bearing 50 for a servo motor in which encoder 52 is located near motor 51. For such models, low dust generation as the rolling bearing 50 is required using a contact seal to prevent malfunction of encoder 52 due to dust generation from inside the bearing and seal wear powder adhering to the encoder 52.

[0004] Prior art includes Patent Documents 1 and 2. Both of these documents propose rolling bearings that can reduce the amount of dust generated from inside the bearing even when the internal pressure of the bearing increases during rotation. Specifically, they specify the relative positions of the core and the secondary lip, the shape of the tip of the contact seal lip that contacts the seal groove, and the inclined surface of the seal groove.

[0005] JP 2022-72083 A JP 2022-102580 A

[0006] The two prior art documents mentioned above are improvement proposals for preventing dust generation from inside the bearing, and there are no problems with the shape proposals in terms of dust generation. Both prior art documents have a structure in which the axial outer surface of the inner ring seal groove makes contact (hereinafter referred to as the inner ring contact portion), which is effective in preventing dust generation from inside the bearing due to increases in internal pressure, and sealing performance is ensured when the inner ring contact portion is in contact.

[0007] Meanwhile, the axial position of this seal after insertion into the bearing is determined by the location where the outer ring seal groove and the bearing side of the seal outer diameter lip come into axial contact (hereinafter referred to as the outer ring contact area). The axial end face of the outer ring seal groove may be angled to take into account factors such as machinability when cutting the seal groove. In this case, if the outer diameter lip follows this angle at the outer ring contact area when the seal is inserted into the bearing, the seal will be positioned at an angle.

[0008] If the seal is positioned in an inclined position, the inner ring contact area will move away from the seal groove, creating a gap. If a gap is created at the inner ring contact area, the seal will not perform adequately. In particular, in conventional seals that contact the outside of the seal groove, the inner ring contact area is inserted with interference. This makes it easy for the seal to fall along the outer ring contact surface due to the reaction force of the interference, making it difficult to ensure stable sealing. Prior literature does not address this issue.

[0009] As mentioned above, the relative axial position of the seal inserted into the bearing and the bearing is determined by the state of contact with the outer ring seal groove. As shown in Figure 13, outer ring contact surface 30 may be inclined, and if seal member 31 is inserted so that it follows the inclination of outer ring contact surface 30, the entire seal member 31 will tilt.

[0010] In particular, in the case of the seal member 31 that contacts the axially outer side of the inner ring seal groove 32, the inner ring seal groove 32 and the inner diameter lip 33 are inserted with interference. Therefore, the reaction force is likely to generate a force F1 in the seal member 31 that causes it to tilt along the outer ring contact surface 30. This tilting reduces the interference and makes the sealing unstable. If preload is applied to the bearing in a tilted state, the relative position of the outer ring 34 and inner ring 35 changes by the amount of the clearance inside the bearing, and in some cases a gap may even occur. This can lead to base oil leakage and a lack of robustness.

[0011] An object of the present invention is to provide a rolling bearing with stable sealing performance.

[0012] A rolling bearing in a first configuration of the present invention comprises an inner ring, an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and a sealing member that seals the bearing space between the inner ring and the outer ring, wherein the outer peripheral portion of the sealing member is fixed to the seal groove of the outer ring and the inner peripheral portion of the sealing member is provided with a lip that contacts the outer surface of the seal groove of the inner ring, and the sealing member is provided with a seal collapse prevention means that prevents the inner peripheral portion from collapsing axially inward.

[0013] With this configuration, the seal tilt prevention means prevents the inner peripheral portion of the seal member from tilting axially inward, i.e., toward the inside of the bearing. This seal tilt prevention means reduces the range of rotational movement of the seal member compared to conventional structures. This stabilizes the seal position after the seal member is inserted into the bearing, and the seal member is less likely to shift position even when subjected to a reaction force caused by contact between the outer surface of the seal groove in the inner ring and the lip. In this way, the sealing performance of the rolling bearing can be stabilized.

[0014] The seal collapse prevention means may have an inclined surface that slopes inward in the axial direction of the inner surface of the outer peripheral portion of the seal member, the inner surface that contacts the seal groove of the outer ring. In this case, the position of the seal member inserted into the bearing is more likely to be stable, thereby more reliably stabilizing sealing performance. Furthermore, robustness is improved because changes in interference due to the bearing are reduced.

[0015] The angle of the inclined surface may be set to satisfy the following relationship with a plane perpendicular to the axial direction: 0° < angle of the inclined surface ≦ inclination angle of the inner surface of the seal groove in the outer ring.In this case, the inclined surface of the seal member is arranged substantially along the inner surface of the seal groove in the outer ring, which makes it easier to stabilize the position of the seal member inserted into the bearing.

[0016] The seal member may be provided with an air hole on its outer circumferential side for releasing the internal pressure of the rolling bearing. In this case, by releasing the internal bearing pressure through the air hole when the rolling bearing rotates, it is possible to suppress excessive changes in the interference of the seal member and the outflow of grease caused by an increase in the internal bearing pressure.

[0017] The sealing member may be provided on only one axial side of the rolling bearing or on both axial sides. When the sealing member is provided on only one axial side, the number of parts and the number of steps required to process the seal grooves, etc., can be reduced, thereby reducing costs. When the sealing members are provided on both axial sides, it is possible to prevent grease from leaking from inside the bearing and foreign matter from entering from the atmosphere side.

[0018] In the two prior art documents mentioned above, the base oil adhering to the bearing side of the seal surface (hereinafter referred to as the "inner seal surface") may run down the seal and reach the tip of the inner lip. In this case, the base oil that has reached the tip of the inner lip may seep out to the outside.

[0019] Specifically, as shown in Figure 28A, the secondary lip 100, which is provided to prevent grease from entering the inner ring seal groove 7 on the inner surface of the seal, protrudes axially inward from the base end. As shown in Figure 28B, when the seal 101 is inserted into the bearing with interference, the secondary lip 100 tilts as the inner diameter lip 102 deforms. The position of the seal 101 changes depending on the mounting state of the bearing. As shown in Figure 29, in a certain seal position, the secondary lip 100 tilts in a direction that causes the base oil Ky to move toward the inner diameter lip tip 103. Therefore, the base oil Ky that reaches the inner diameter lip tip 103 may seep out when the inner ring 104 rocks.

[0020] A rolling bearing in a second configuration of the present invention comprises an inner ring, an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and a sealing member that seals the bearing space between the inner ring and the outer ring, the sealing member having a main lip that contacts the seal groove of the inner ring and a secondary lip that protrudes axially inward from the base end and does not contact the seal groove, and the rolling bearing has grease sealed in the bearing space, and the sealing member is provided with grease flow obstruction means that obstructs the flow of grease from the inner surface of the secondary lip to the inner diameter side tip of the main lip.

[0021] With this configuration, the grease flow obstruction means obstructs the flow of grease from the inner circumferential surface of the secondary lip to the inner diameter side tip of the main lip, preventing the base oil of the grease running along the inner surface of the seal from reaching the inner diameter side tip of the main lip, thereby reducing the amount of dust generated from inside the bearing compared to conventional structures.

[0022] The grease flow obstruction means includes a shape in which the inner peripheral surface of the secondary lip is inclined toward the outer diameter side as it goes axially outward. When the axial direction of the rolling bearing is set along the horizontal axis, the base oil of the grease that flows along the inner surface of the seal can be more reliably prevented from accumulating on the inner peripheral surface of the secondary lip and flowing to the tip of the inner diameter side of the primary lip.

[0023] The grease flow obstruction means may have an uneven portion formed between the inner peripheral surface of the secondary lip and the axially inner surface of the primary lip. The surface from the inner peripheral surface of the secondary lip to the axially inner surface of the primary lip is referred to as the "seal back surface." In this case, the base oil of the grease flowing along the inner surface of the seal is blocked by the seal back surface and is allowed to escape in the circumferential direction.

[0024] The seal member may be provided with an air hole on its outer circumferential side for releasing the internal pressure of the rolling bearing. In this case, by releasing the internal bearing pressure through the air hole when the rolling bearing rotates, it is possible to suppress excessive changes in the interference of the seal member and the outflow of grease caused by an increase in the internal bearing pressure.

[0025] The sealing member may be provided on only one axial side of the rolling bearing or on both axial sides. When the sealing member is provided on only one axial side, the number of parts and the number of steps required to process the seal grooves, etc., can be reduced, thereby reducing costs. When the sealing members are provided on both axial sides, it is possible to prevent grease from leaking from inside the bearing and foreign matter from entering from the atmosphere side.

[0026] Any combination of at least two features disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more of the claims is included in the present invention.

[0027] The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and explanation, and should not be used to define the scope of the present invention, which is defined by the appended claims. In the accompanying drawings, the same reference numerals in multiple drawings indicate the same or corresponding parts.

[0028] 1 is a longitudinal sectional view of a rolling bearing according to a first embodiment of the present invention. FIG. 2 is a perspective view of a cage of the rolling bearing. FIG. 3 is an enlarged sectional view showing a seal member of the rolling bearing. FIG. 4 is an enlarged sectional view of the lip and other parts of the seal member. FIG. 5 is an enlarged sectional view showing a comparison of the outer peripheral side portions of the seal member and a conventional seal member. FIG. 6 is an enlarged sectional view showing the outer peripheral side portions of the seal member and a conventional seal member together with the seal groove of the outer ring. FIG. 7 is a perspective view of the seal member of the rolling bearing. FIG. 8 is an enlarged sectional view showing the outer peripheral side portion of the seal member in a rolling bearing according to a second embodiment of the present invention. FIG. 9 is an enlarged sectional view showing a modified example of the seal member. FIG. 10 is a longitudinal sectional view of a rolling bearing according to a third embodiment of the present invention. FIG. 11 is a longitudinal sectional view of a rolling bearing according to a fourth embodiment of the present invention. FIG. 12 is a longitudinal sectional view of a rolling bearing according to a fifth embodiment of the present invention. FIG. 13 is a schematic view of a rolling bearing for a servo motor, etc. FIG. 14 is a view for explaining problems with conventional rolling bearings. FIG. 15 is a longitudinal sectional view of a rolling bearing according to a sixth embodiment of the present invention. FIG. 16 is a perspective view of a cage of the rolling bearing. FIG. 17 is an enlarged sectional view showing the seal member of the rolling bearing. FIG. 10 is an enlarged cross-sectional view of a grease flow obstruction means etc. of the seal member. FIG. 11 is an enlarged cross-sectional view of a main part for explaining the effect of the seal member. FIG. 12 is a perspective view of the seal member. FIG. 13 is an enlarged cross-sectional view of a main part of a seal member in a rolling bearing according to a seventh embodiment of the present invention. FIG. 14 is an enlarged cross-sectional view of a main part showing a modified example of the seal member. FIG. 15 is an enlarged cross-sectional view of a main part for explaining the effect when the attitude of the seal member is different. FIG. 16 is an enlarged cross-sectional view of a main part of a seal member in a rolling bearing according to an eighth embodiment of the present invention. FIG. 17 is a longitudinal cross-sectional view of a rolling bearing according to a ninth embodiment of the present invention. FIG. 18 is a longitudinal cross-sectional view of a rolling bearing according to a tenth embodiment of the present invention. FIG. 19 is a longitudinal cross-sectional view of a rolling bearing according to an eleventh embodiment of the present invention. FIG. 19 is a schematic view of a rolling bearing for a servo motor etc. FIG. 19 is an enlarged cross-sectional view of a main part of a conventional seal member showing a state before contact with a seal groove. FIG. 19 is an enlarged cross-sectional view of a main part showing a state after contact with the seal groove. FIG. 19 is an enlarged cross-sectional view of a main part showing the flow of base oil adhering to the inner seal surface of the seal member.

[0029] [First embodiment] A rolling bearing according to an embodiment of the present invention will be described with reference to Figures 1 to 7. This rolling bearing is applied to, for example, industrial machinery such as servo motors, vehicles, etc. However, the rolling bearing is not limited to these uses and can be applied to various types of machinery, devices, etc.

[0030] <Schematic Configuration of Rolling Bearing> Fig. 1 is a cross section (longitudinal cross section) of a rolling bearing 1 taken along a plane including the axial direction. The same applies to cross sections of other embodiments. The rolling bearing 1 is a deep groove ball bearing comprising an inner ring 2, an outer ring 3, balls (rolling elements) 4, a cage 5, and a seal member 6. A plurality of balls 4 are interposed between raceway surfaces 2a, 3a of the inner and outer rings 2, 3 and are held at regular intervals in the circumferential direction by the cage 5. The seal member 6 is attached to the outer ring 3 and closes the bearing space, which is the annular space between the inner ring 2 and the outer ring 3. In this example, seal members 6, 6 are attached to both axial sides of the inner circumferential surface of the outer ring. A lubricant such as grease is sealed in the bearing space between the inner and outer rings 2, 3.

[0031] In this specification, a rolling bearing may be simply referred to as a "bearing." In the following description, the direction of the bearing center axis AX, which is the bearing shaft center, is referred to as the "axial direction," the direction perpendicular to the bearing center axis AX is referred to as the "radial direction," and the direction around the bearing center axis AX is referred to as the "circumferential direction." In addition, the side facing the bearing center axis AX is referred to as the "inner diameter side," and the side away from the bearing center axis AX is referred to as the "outer diameter side."

[0032] <Cage> As shown in FIG. 2, the cage 5 in this example is made of synthetic resin and is a two-piece cage consisting of two identically shaped annular bodies 5a, 5a mated together. This cage 5 holds balls 4 (FIG. 1) in pockets Pt, which have a cylindrical axial pocket shape. Each annular body 5a has multiple semi-cylindrical pocket walls 5c and multiple connecting plates 5b. The two pocket walls 5c, 5c are mated with each other in the axial direction to form pockets Pt. The pockets Pt are evenly spaced around the circumference. The cage 5 has engaging holes Ka and engaging claws Kb that engage with each other on the connecting plates 5b between the pockets Pt. The cage 5 is assembled by engaging the engaging claws Kb with the engaging holes Ka and mating the two identically shaped annular bodies 5a, 5a. The pockets of the cage 5 may also have a spherical shape.

[0033] <Regarding seal structure, etc.> As shown in Figure 1 , each seal member 6 is a contact seal in which a lip 15 contacts a seal groove 7 in the inner ring 2. Seal grooves 7 are formed in the circumferential direction on the outer peripheral surface of the inner ring 2, and seal grooves 9 for fixing the seal member are provided on the inner peripheral surface of the outer ring 3 opposite each seal groove 7. As shown in Figure 3 , the seal member 6 is formed by molding a rubber material 11 onto a core metal 10, and an outer peripheral portion 8 of the seal member 6 is fitted into and fixed in the seal groove 9 of the outer ring 3.

[0034] <Outer Ring Seal Groove> The seal groove 9 of the outer ring 3 has, in order axially outward, an inner surface 9a, a groove bottom surface 9c, and an outer surface 9b. As shown in FIG. 1 , the inner surface 9a connects to outer ring shoulders provided on both axial sides of the raceway surface 3a. The inner surface 9a is formed as an inclined surface that slopes radially outward in the axial direction, taking into consideration machinability and other factors when cutting the seal groove 9. As shown in FIG. 3 , the groove bottom surface 9c, which smoothly connects to the inner surface 9a, is recessed radially outward. The outer surface 9b is formed as an inclined surface that smoothly connects to the groove bottom surface 9c and slopes radially inward in the axial direction. The outer peripheral portion 8 of the seal member 6 has an interference (not shown) and is fitted and fixed in the seal groove 9 in an elastically deformed state.

[0035] A lip 15 is provided on an inner peripheral portion 13 of the seal member 6, which contacts the outer surface 7c of the seal groove 7 of the inner ring 2. In Figures 1 and 3, a portion of the lip 15 of the seal member 6 is shown as being embedded in the seal groove 7 of the inner ring 2, but this portion is an interference and actually contacts the seal groove 7 in an elastically deformed state. The same applies to the seal structures in Figures 9 to 11, which will be described later.

[0036] <Air holes> As shown in Figure 7, a plurality of air holes 12 are provided in the outer peripheral portion 8 (Figure 3) of the seal member 6 to release the internal pressure of the rolling bearing. These air holes 12 include radial air holes 12a, 12a formed along the radial direction and axial air holes 12b formed along the axial direction. The air holes 12a, 12b are each formed by grooves provided in the outer peripheral portion of the seal member 6. The radial air holes 12a, 12a and the axial air hole 12b are provided at different circumferential positions. The number and circumferential positions of the air holes 12a, 12b are not limited to those shown in Figure 7.

[0037] 3 and 7, the radial air holes 12a, 12a and the axial air hole 12b communicate with each other via the groove bottom surface 9c of the seal groove 9. Therefore, when the rolling bearing 1 (FIG. 1) is rotating, the internal bearing pressure can be released to the outside from the two radial air holes 12a, 12a via the axial air hole 12b.

[0038] <Inner ring seal groove> As shown in Figure 1, the seal groove 7 of the inner ring 2 has, in order axially outward, an inner side surface 7a, a groove bottom surface 7b, and an outer side surface 7c. Here, in the seal groove 7, the side surface facing the inside of the bearing is called the inner side surface 7a, and the side surface facing the outside of the bearing is called the outer side surface 7c. The inner side surface 7a connects to inner ring shoulders provided on both axial sides of the raceway surface 2a and forms an inclined surface that slopes toward the inner diameter as it extends axially outward. The groove bottom surface 7b, which smoothly connects to this inner side surface 7a, has a shape that is recessed toward the inner diameter. The outer side surface 7c connects smoothly to the groove bottom surface 7b and forms an inclined surface that slopes toward the outer diameter as it extends axially outward.

[0039] As shown in FIG. 3, nitrile rubber is typically used as the material for the rubber material 11 in the seal member 6, but other materials such as acrylic rubber, silicone rubber, or fluororubber may also be used depending on the operating temperature.

[0040] <Lip> As shown in Figure 4, the inner peripheral portion 13 of the seal member 6, which extends radially inward beyond the inner diameter of the core metal 10, is made of the rubber material 11. The inner peripheral portion 13 has a constricted portion 14 whose thickness decreases toward the inner diameter, and a main lip 15 and a sub-lip 16 connected to the constricted portion 14. The constricted portion 14, main lip 15, and sub-lip 16 are integrally molded. "Integral molding" means that the constricted portion 14, main lip 15, and sub-lip 16 are not formed by combining multiple elements, but are molded as part or the whole of a single object from a single material, for example, by injection molding.

[0041] A main lip 15 is connected to the inner diameter end of the constricted portion 14, and a secondary lip 16 protrudes axially inward from the inner surface of a base end 15a of the main lip 15. As shown in Figure 1, a labyrinth seal Rs is formed between the tip end of the secondary lip 16 and the inner surface 7a of the seal groove 7.

[0042] 4, the main lip 15 has a base end 15a that slopes inward in the axial direction, a lip main body 15b that extends inward from the base end 15a, and a tip end 15c that is provided on the outer surface portion of the lip main body 15b on the tip side. The tip end 15c of the main lip 15 is formed in an R-shape that abuts the outer surface 7c of the seal groove 7 in the normal direction. The outer diameter surface 15ca of the tip end 15c of the main lip 15 slopes inward in the axial direction and smoothly connects to the R-shape.

[0043] <Seal collapse suppression means> As shown in Figure 3, the seal member 6 is equipped with a seal collapse suppression means St that suppresses the inner peripheral portion 13 from collapsing axially inward. Specifically, the seal collapse suppression means St is provided in such a manner that the inner surface 8a of the outer peripheral portion 8 of the seal member 6, which comes into contact with the seal groove 9 of the outer ring 3, has an inclined surface 8aa that slopes inward in the axial direction. Here, the side surface of the outer peripheral portion 8 of the seal member 6 facing the inside of the bearing is referred to as the inner surface 8a. The axially inner side refers to the direction toward the inside of the bearing.

[0044] 5A and 5B are enlarged cross-sectional views comparing the outer peripheral portions 8, 80 of the seal member 6 of this embodiment (FIG. 5B) with the outer peripheral portion 80 of a conventional seal member 60 (FIG. 5A). In the conventional example of FIG. 5A, the inner surface 80a of the outer peripheral portion 80 of the seal member 60 is formed on a plane perpendicular to the axial direction. In this case, as shown in FIG. 6A, when the seal member 60 is inserted so as to follow the inclination of the inner surface 9a, the entire seal member 60 has a large range of rotational movement, and the entire seal member 60 tilts axially inward.

[0045] In contrast, in the seal member 6 shown in Figure 5(b), the inner surface 8a of the outer peripheral portion 8 has the aforementioned inclined surface 8aa. The angle α of this inclined surface 8aa is set to satisfy the following relationship with respect to a plane perpendicular to the axial direction, as shown in Figure 6(b): 0° < inclined surface angle α ≦ inclination angle of the inner surface 9a in the seal groove 9 of the outer ring 3. It is more preferable that the inclined surface angle α be set to satisfy the following relationship with respect to a plane perpendicular to the axial direction: inclination angle of the inner surface 9a in the seal groove 9 of the outer ring 3 - 1° ≦ inclination angle of the inclined surface 9a in the seal groove 9 of the outer ring 3

[0046] <Operation and Effect> In the rolling bearing 1 of Fig. 1 described above, the seal collapse suppression means St suppresses the entire seal member 6, including the inner peripheral portion 13 (Fig. 3), from collapsing axially inward. As shown in Fig. 6(b), the seal collapse suppression means St has an inclined surface 8aa on the inner surface 8a of the outer peripheral portion 8 of the seal member 6, which contacts the seal groove 9 of the outer ring 3, that slopes inward in the axial direction. This inclined surface 8aa reduces the range of rotational movement of the seal member 6 compared to conventional structures.

[0047] This stabilizes the seal position of the seal member 6 when it is inserted into the bearing, and the position of the seal member 6 is less likely to shift even when subjected to a reaction force caused by contact between the lip 15 and the outer surface 7c of the seal groove 7 of the inner ring 2 shown in Figure 3. This stabilizes the sealing performance of the rolling bearing. Furthermore, robustness is improved because there is less change in interference due to the bearing.

[0048] As shown in Figure 7, air holes 12 for releasing the internal pressure of the rolling bearing 1 (Figure 1) are provided on the outer circumferential side of the seal member 6. Therefore, by releasing the internal bearing pressure through the air holes 12 when the rolling bearing 1 (Figure 1) is rotating, it is possible to suppress excessive changes in the interference of the seal member 6 and the outflow of grease caused by an increase in internal bearing pressure.

[0049] <Regarding Other Embodiments> In the following description, parts corresponding to matters previously described in each embodiment are assigned the same reference numerals, and duplicated description will be omitted. When only part of the configuration is described, the other parts of the configuration are the same as those in the previously described embodiment unless otherwise specified. The same configuration produces the same effects. It is possible to combine not only the parts specifically described in each embodiment, but also parts of the embodiments together, provided that there is no particular problem with the combination.

[0050] [Second embodiment: FIG. 8A, inclined surface + flat surface] As shown in FIG. 8A, the inner surface 8a of the outer peripheral portion 8 of the seal member 6 may have an inclined surface 8aa and a flat surface 8ab connected to the inner diameter edge of the inclined surface 8aa. The flat surface 8ab is, for example, provided parallel to a plane perpendicular to the axial direction. In this case, the flat surface 8ab can be used as a reference surface when determining the angle α of the inclined surface 8aa. This allows for more accurate determination of the angle α of the inclined surface 8aa, making it easier to stabilize the seal position when the seal member 6 is inserted into a bearing. Other advantages similar to those of the previous embodiment are also achieved.

[0051] [Modification: Fig. 8B , Inclined Surface + Flat Surface + Convex Portion] As shown in Fig. 8B , a plurality of convex portions 17 may be provided in the circumferential and radial directions on the flat surface 8ab. When this seal member 6 is inserted into the bearing, the protruding tip portions of each convex portion 17 contact the inner surface of the seal groove in the outer ring in a state of elastic deformation. In this case, the pressing force of each convex portion 17 makes it easier to stabilize the sealing position of the seal member 6 when inserted into the bearing than the seal structure of Fig. 8A .

[0052] [Third embodiment: Fig. 9, one-sided seal] As shown in Fig. 9, the seal member 6 may be provided on only one axial side of the rolling bearing 1. In this case, it is possible to reduce the number of parts and the number of steps required to process the seal grooves, etc., compared to a rolling bearing provided with seal members on both axial sides, thereby reducing costs.

[0053] [Fourth embodiment: Fig. 10, crown-shaped cage] As shown in Fig. 10, the cage 5 may be a so-called crown-shaped cage having a shape in which one axial side of the pocket Pt is open. In this case, the number of parts of the cage 5 can be reduced compared to the above-mentioned two-piece cage, thereby reducing the number of assembly steps.

[0054] [Fifth embodiment: FIG. 11, one-sided seal] As shown in FIG. 11, in a rolling bearing 1 having a crown-shaped cage 5, a seal member 6 may be provided on only one axial side of the rolling bearing 1.

[0055] 14 to 19 show rolling bearings according to embodiments of the present invention. As shown in Fig. 14, the rolling bearing 1 according to the sixth embodiment has the same general configuration as the rolling bearing according to the first embodiment described above. In the sixth embodiment, components similar to those in the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0056] 14 and 16, part of the outer peripheral portion of the seal member 6 is shown as being embedded in the seal groove 9 of the outer ring 3, but this part is an interference, and in reality the seal member 6 is fitted into the seal groove 9 in an elastically deformed state. The same applies to the seal structures in Figures 24 to 26, which will be described later.

[0057] As shown in Figure 17, the secondary lip 16 protrudes axially inward from its base end 16a and, as shown in Figure 14, is not in contact with the seal groove 7 of the inner ring 2. A labyrinth seal Rs is formed between the tip end of the secondary lip 16 and the inner surface 7a of the seal groove 7. Here, "axially inward" refers to the direction from the base end 16a toward the inside of the bearing.

[0058] As shown in FIG. 17, the tip portion 15c of the main lip 15 is also referred to as an inner diameter side tip portion 15c.

[0059] 18A , the seal member 6 is provided with a grease flow obstruction means Gs that obstructs the flow of grease from the inner circumferential surface 16b of the secondary lip 16 to the inner diameter side tip 15c of the primary lip 15. The grease flow obstruction means Gs includes a shape (reverse inclination shape) in which the inner circumferential surface 16b of the secondary lip 16 slopes toward the outer diameter side as it moves axially outward. Here, the direction from the secondary lip 16 toward the outside of the bearing is referred to as the axial outward direction.

[0060] As shown in Figure 17, even when the inner diameter side tip portion 15c is in contact with the seal groove 7, the inner circumferential surface 16b of the secondary lip 16 is configured to be inclined toward the outer diameter side as it moves axially outward. As shown in Figure 18A, the inclination angle α of the inner circumferential surface 16b with respect to the axial direction is set to, for example, approximately 1° to 20° through testing or simulation. However, the inclination angle α is not limited to this angle. In this example, the entire inner circumferential surface 16b of the secondary lip 16 has a reverse inclined shape, but this shape is not limited thereto. For example, a portion of the inner circumferential surface 16b in the axial direction may have a reverse inclined shape, and the other portion of the inner circumferential surface 16b may have a flat shape that is approximately parallel to the axial direction.

[0061] <Effects> As shown in Figure 18B, the grease flow obstruction means Gs includes a reverse-inclined shape in which the inner circumferential surface 16b of the secondary lip 16 slopes radially outward as it moves axially outward. This reverse-inclined shape of the secondary lip 16 obstructs the flow of grease FL from the inner circumferential surface 16b of the secondary lip 16 to the inner diameter side tip 15c of the primary lip 15. In other words, when the axial direction of the rolling bearing is aligned horizontally, the base oil Ky of the grease flowing along the inner seal surface is retained on the inner circumferential surface 16b of the secondary lip 16, more reliably preventing it from flowing to the inner diameter side tip 15c of the primary lip 15. This reduces the amount of dust generated from inside the bearing compared to conventional structures.

[0062] 17 , the main lip 15 has a base end 15a that slopes axially outward and therefore radially inward, and a lip main body 15b that extends radially inward from the base end 15a. This maintains the ability of the main lip 15 to follow the seal groove 7 of the inner ring 2, and the main lip 15 contacts the outer surface 7c of the seal groove 7 with a desired interference (pressing force). In addition to the base end 15a and lip main body 15b, the inner diameter side tip 15c that connects to the lip main body 15b is formed in an R-shape that abuts the outer surface 7c of the seal groove 7 in the normal direction.

[0063] As a result, even if the internal bearing pressure rises during rotation of the rolling bearing 1 (FIG. 14), the main lip 15 can prevent foreign matter from entering from the atmosphere and can also prevent changes in the surface pressure distribution of the main lip 15. This makes it possible to prevent undesirable increases in torque and undesirable heat generation by the main lip 15.

[0064] [Seventh Embodiment: FIGS. 20 to 22, Uneven Portion] As shown in FIG. 20, the grease flow obstruction means Gs may be provided with an uneven portion Un between the inner circumferential surface 16b of the secondary lip 16 and the seal back surface, which is the surface extending from the axially inner surface 15d of the primary lip 15. In this example, the uneven portion Un is provided over the entire inner circumferential surface 16b of the secondary lip 16 and the axially inner surface 15d of the primary lip 15 (the area indicated by the bold line in FIG. 20). As shown in FIG. 21, a convex portion 15ba protruding axially inward may be provided on the inner surface of the lip main body 15b. The seal back surface Sm excluding this convex portion 15ba corresponds to a concave portion. In the second embodiment, the uneven portion Un (FIG. 20) consisting of the concave portion and the convex portion 15ba constitutes the grease flow obstruction means Gs.

[0065] With this configuration, the base oil Ky of the grease that flows along the inner surface of the seal is blocked by the convex portion 15ba of the seal back surface Sm and is released in the circumferential direction, more so than in the sixth embodiment. Even when the axial direction of the rolling bearing is aligned vertically, that is, even when the seal member 6 is in the position shown in Figure 22, the base oil Ky of the grease is blocked by the convex portion 15ba of the seal back surface Sm. This makes it possible to reduce the amount of dust generated from inside the bearing compared to conventional structures.

[0066] Eighth embodiment: FIG. 23 , reverse slope + convex portion As shown in FIG. 23 , the inner peripheral surface 16b of the secondary lip 16 may have a reverse slope that slopes radially outward as it extends axially outward, combined with the convex portion 15ba described above. In this case, the possibility of the grease base oil flowing onto the seal back surface Sm is reduced. Furthermore, even if the base oil does flow onto the seal back surface Sm, it is blocked by the convex portion 15ba, making it difficult for it to reach the inner diameter side tip portion 15c of the primary lip 15. This reduces the amount of dust generated from inside the bearing compared to conventional structures.

[0067] 24, a seal member 6 may be provided on only one axial side of the rolling bearing 1. In this case, the number of parts can be reduced and the number of steps required to process the seal grooves, etc. can be reduced, resulting in cost savings, compared to a rolling bearing provided with seal members on both axial sides.

[0068] [Tenth embodiment: Fig. 25, crown-shaped cage] As shown in Fig. 25, the cage 5 may be a so-called crown-shaped cage having an opening on one axial side of the pocket Pt. In this case, the number of parts of the cage 5 can be reduced compared to the two-piece cage described above, thereby reducing the number of assembly steps.

[0069] [Eleventh embodiment: FIG. 26, one-sided seal] As shown in FIG. 26, in a rolling bearing 1 having a crown-shaped cage 5, a seal member 6 may be provided on only one axial side of the rolling bearing 1.

[0070] In each embodiment, it is possible to omit or increase the number of air holes in the outer peripheral portion of the seal member. That is, the seal member may be configured to have no air holes or to have multiple air holes. A steel plate wave cage may be used in a deep groove ball bearing. Rolling bearings equipped with seal tilt prevention means or grease flow obstruction means are not limited to deep groove ball bearings, but can be applied to various types of bearings, such as angular contact ball bearings, tapered roller bearings, and cylindrical roller bearings.

[0071] As described above, the preferred embodiment has been described with reference to the drawings, but various additions, modifications, and deletions can be made without departing from the spirit of the present invention. Therefore, such additions, modifications, and deletions are also included in the scope of the present invention.

[0072] DESCRIPTION OF SYMBOLS 1... rolling bearing 2... inner ring 3... outer ring 4... ball (rolling element) 6... seal member 7... seal groove 8... outer peripheral portion 8a... inner surface 8aa... inclined surface 9... seal groove 9b... outer surface 12a, 12b... air holes 13... inner peripheral portion 15... lip 15c... inner diameter side tip portion 15d... axial inner surface 16... secondary lip 16b... inner peripheral surface Gs... grease flow obstruction means St... seal collapse prevention means Un... uneven portion

Claims

1. A rolling bearing comprising an inner ring, an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and a seal member that seals the bearing space between the inner ring and the outer ring, wherein the outer peripheral portion of the seal member is fixed in a seal groove of the outer ring, and the inner peripheral portion of the seal member is provided with a lip that contacts the outer surface of the seal groove of the inner ring, and the seal member is equipped with seal collapse prevention means that prevents the inner peripheral portion from collapsing axially inward.

2. A rolling bearing as claimed in claim 1, wherein the seal collapse prevention means is a rolling bearing in which the inner surface of the outer peripheral portion of the seal member that comes into contact with the seal groove of the outer ring has an inclined surface that slopes inwards in the axial direction towards the inner diameter.

3. A rolling bearing according to claim 2, wherein the angle of the inclined surface is set to satisfy the following relationship with respect to a plane perpendicular to the axial direction: 0° < angle of the inclined surface ≦ inclination angle of the inner surface of the seal groove of the outer ring 4. A rolling bearing according to claim 2 or 3, wherein an air hole is provided on the outer peripheral portion of the seal member to release the internal pressure of the rolling bearing.

5. A rolling bearing according to claim 2 or 3, wherein the sealing member is provided on only one axial side of the rolling bearing or on both axial sides thereof.

6. A rolling bearing comprising an inner ring, an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and a sealing member sealing the bearing space between the inner ring and the outer ring, the sealing member having a main lip that contacts the seal groove of the inner ring and a secondary lip that protrudes axially inward from its base end and does not contact the seal groove, the bearing space being filled with grease, and the sealing member having grease flow obstruction means that obstructs the flow of grease from the inner surface of the secondary lip to the inner diameter side tip of the main lip.

7. A rolling bearing according to claim 6, wherein the grease flow obstruction means includes a shape in which the inner peripheral surface of the secondary lip is inclined toward the outer diameter side as it moves axially outward.

8. A rolling bearing as set forth in claim 6 or claim 7, wherein the grease flow obstruction means has an uneven portion provided between the inner peripheral surface of the secondary lip and the axially inner surface of the primary lip.

9. A rolling bearing according to claim 6 or 7, wherein an air hole is provided on the outer peripheral portion of the seal member to release the internal pressure of the rolling bearing.

10. A rolling bearing according to claim 6 or 7, wherein the sealing member is provided on only one axial side of the rolling bearing or on both axial sides thereof.

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